Process for the preparation of diphenylmethane dicarbamates and polymethylene polyphenyl carbamates using solid acid catalysts

ABSTRACT

Diphenylmethane dicarbamates and polymethylene polyphenyl carbamate homologs and derivatives of these compounds are produced by the condensation of N-aryl carbamic acid esters, such as ethylphenylcarbamate, with formaldehyde, para-formaldehyde or trioxane in the presence of strongly acidic sulfonated aromatic ion exchange resins or perfluoroalkane sulfonic acid resins, at temperatures of from ambient to about 150° C. and optionally in the presence of an inert solvent.



